Electronic device comprising flexible display having expandable display area

ABSTRACT

The disclosure discloses an electronic device including a flexible display having an expandable display area. The disclosed electronic device may include: a housing including a first cover disposed to face a first direction, a second cover disposed to face a second direction opposite to the first direction, and a side member enclosing at least part of a space between the first and second covers; a slider to be inserted or withdrawn by being disposed to at least part of an area of the first cover of the housing; a flexible display disposed in the slider such that at least part thereof is exposed, and disposed to allow a display area to be expanded according to the withdrawing of the slider and allow the expanded display area to be hidden inside the housing; and a support body mounted closely in contact on a bottom face of the flexible display, supporting the expanded display area as a prop when the slider is withdrawn, and disposed to be housed inside the housing together with the expanded display area when the slider is inserted.

TECHNICAL FIELD

Various embodiments of the disclosure relate to an electronic deviceincluding a flexible display having an expandable display area.

BACKGROUND ART

An electronic device may include a flexible display to expand a displayarea of the flexible display. For example, the flexible display may bemounted on the electronic device in a curved, foldable, or rollablemanner.

For example, the flexible display may be mounted with a rolling typeinside the electronic device to provide an expanded display area whenthe flexible display is withdrawn. The expanded display area may providea new user interfacing environment.

DISCLOSURE OF INVENTION Technical Problem

However, the electronic device including the flexible display may nothave good smoothness of the expanded display area.

In particular, the electronic device including the conventional flexibledisplay may be scratched on a surface due to interference in a processof expanding the display area.

Solution to Problem

Various embodiments of the disclosure may provide a device capable ofmaintaining smoothness of an expanded display area of a flexibledisplay.

Various embodiments of the disclosure may provide an electronic devicecapable of preventing a surface scratch of a flexible display.

Various embodiments of the disclosure may provide an electronic devicecapable of sufficiently ensuring a space for mounting a component insidea main body.

Various embodiments of the disclosure may provide a new interfacingenvironment to a user by providing various screen ratios of a displayarea.

An electronic device according to various embodiments of the disclosuremay include: a housing including a first cover disposed to face a firstdirection, a second cover disposed to face a second direction oppositeto the first direction, and a side member enclosing at least part of aspace between the first and second covers; a slider to be inserted orwithdrawn by being disposed to at least part of an area of the firstcover of the housing; a flexible display disposed in the slider suchthat at least part thereof is exposed, and disposed to allow a displayarea to be expanded according to the withdrawing of the slider and allowthe expanded display area to be hidden inside the housing; and a supportbody mounted closely in contact on a bottom face of the flexibledisplay, supporting the expanded display area as a prop when the slideris withdrawn, and disposed to be housed inside the housing together withthe expanded display area when the slider is inserted.

Advantageous Effects of Invention

An electronic device according to various embodiments of the disclosurecan maintain smoothness of an expanded display area, and can prevent asurface scratch of the expanded display area when inserted/withdrawn.

In addition, an electronic device according to various embodiments ofthe disclosure can provide various screen ratios of a display area toprovide a new user interfacing environment.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating an electronic device in whicha slider is inserted according to various embodiments of the disclosure;

FIG. 2 is a perspective view illustrating an electronic device in whicha slider is withdrawn to expand a display area according to variousembodiments of the disclosure;

FIG. 3 is a cross-sectional view illustrating an electronic device inwhich a slider is inserted according to various embodiments of thedisclosure;

FIG. 4 is a cross-sectional view illustrating an electronic device inwhich a slider is withdrawn to expand a display area according tovarious embodiments of the disclosure;

FIG. 5 is an exemplary view illustrating a structure of a smoothnessmaintaining device mounted on an electronic device according to variousembodiments of the disclosure;

FIG. 6 is an exemplary view briefly illustrating a state where a firstroller of a smoothness maintaining device is supported by an elasticbody according to various embodiments of the disclosure;

FIG. 7A is a cross-sectional view illustrating various examples ofsupport bodies according to various embodiments of the disclosure; FIG.7B is a cross-sectional view illustrating various examples of supportbodies according to various embodiments of the disclosure; FIG. 7C is across-sectional view illustrating various examples of support bodiesaccording to various embodiments of the disclosure;

FIG. 8 is a cross-sectional view illustrating an anti-scratch device ofan expanded display area according to various embodiments of thedisclosure; and

FIG. 9 is an exemplary view briefly illustrating an automaticinserting/withdrawing device included in an electronic device accordingto various embodiments of the disclosure.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, various embodiments of the disclosure are described withreference to the accompanying drawings. However, it should beappreciated that this is not intended to limit the technologicalfeatures set forth herein to particular embodiments and include variouschanges, equivalents, or replacements for an embodiment of thedisclosure. With regard to the description of the drawings, similarreference numerals may be used to refer to similar or related elements.

An electronic device according to various embodiments of the disclosuremay include at least one of, for example, a smart phone, a tabletPersonal Computer (PC), a mobile phone, a video phone, an e-book reader,a desktop PC, a laptop PC, a netbook computer, a workstation, a server,a Personal Digital Assistant (PDA), a Portable Multimedia Player (PMP),a MPEG-1 Audio Layer 3 (MP3) player, a mobile medical device, a camera,and a wearable device (e.g., smart glasses, a Head-Mounted Display(HMD), electronic clothes, an electronic bracelet, an electronicnecklace, an electronic appcessory, an electronic tattoo, a smartmirror, or a smart watch).

FIG. 1 is a perspective view illustrating an electronic device in whicha slider is inserted according to various embodiments of the disclosure.FIG. 2 is a perspective view illustrating an electronic device in whicha slider is withdrawn to expand a display area according to variousembodiments of the disclosure.

Referring to FIG. 1 and FIG. 2, an electronic device 100 according tovarious embodiments of the disclosure may include a main body 110, aslider 120, and a flexible display 130. The slider 120 may be insertedto or withdrawn from the main body 110. FIG. 1 illustrates a state wherethe slider 120 is inserted to the main body 110, and FIG. 2 illustratesa state where the slider 120 is withdrawn from the main body 110. ACartesian coordinate system is used, where an X-axis may be a horizontaldirection of the electronic device 100, a Y-axis may be a verticaldirection of the electronic device 100, and a Z-axis may be a thicknessdirection of the electronic device 100. A Y(+)-axis may mean a directionof withdrawing the slider 120. A Y(−)-axis may mean a direction ofinserting the slider 120. An X-axis may mean a direction of a rotationaxis of first and second rollers, and a direction of disposing aprotrusion portion.

The main body 110 according to various embodiments may include a housing111. The housing 111 according to various embodiments may include afirst face (a first cover or a front face) facing a first direction, asecond face (a second cover or a bottom face) facing a second directionopposite to the first direction, and a side member 112 enclosing atleast part of a space surrounded by the first and second faces. Thefirst direction may refer to a vertical upward direction of the flexibledisplay 130, and the second direction may refer to a vertical downwarddirection of the flexible display 130. For example, the slider 120 maybe disposed to be exposed in a first direction of the housing 111, andthe flexible display 130 may be disposed to be exposed in a firstdirection of the slider 120.

The housing 111 according to various embodiments may include a printedcircuit board, a battery, an antenna, a connector hole, and at least onekey input device, or the like (not shown).

The key input device according to various embodiments may include a homekey (not shown) disposed to the housing 110 and/or a side key button 114disposed to the side member 112 of the housing 111. In anotherembodiment, the electronic device 100 may not include all or some of theaforementioned key input devices, and the key input device not includedmay be implemented on the flexible display 130 in other forms such assoft keys.

A connector hole (not shown) according to various embodiments mayinclude a first connector hole (not shown) capable of housing aconnector (e.g., a USB connector) for transmitting and receiving powerand/or data with respect to an external electronic device, and/or asecond connector hole (e.g., an earphone jack) (not shown) capable ofhousing a connector for transmitting and receiving an audio signal withrespect to the external electronic device.

The slider 120 according to various embodiments may be withdrawn fromthe housing 111 while maintaining a horizontal state, and may beinserted to the housing 111 while maintaining the horizontal state. Forexample, a driving source for inserting or withdrawing the slider 120may be implemented to be manual, semi-automatic, or automatic. When thedriving source for inserting/withdrawing the slider 120 issemi-automatic, the semi-automatic driving source may be constructed ofan elastic body or the like. When the driving force forinserting/withdrawing the slider 120 is automatic, it may be constructedof a gear mechanism, a driving motor, or the like (see FIG. 9).

In the electronic device 100 according to various embodiments, a displayarea of the flexible display 130 may be expanded when the slider 120 iswithdrawn from the housing 111. For example, the flexible display 130may include a display area 132 exposed always and an expanded displayarea 134 expanded when the slider 120 is withdrawn.

The flexible display 130 according to various embodiments may be mountedto be exposed at least in part on an upper face of the slider 120, andone end thereof may be fixed to the slider 120. Thus, when the slider120 is withdrawn, one end of the flexible display 130 is pulled in awithdrawing direction, thereby expanding the display area. When theslider 120 is inserted, the expanded display area 134 may be housedinside the housing 111. For example, a receiver 121, a camera module122, an indicator 123, and at least one sensor 124 may be disposed tothe upper face of the slider 120. The camera module 122 may be disposedto one side with respect to the receiver 121, and the indicator 123 andthe sensor 124 may be disposed to the other side.

The camera 122 according to various embodiments may include one or morelenses, an image sensor, and/or an image signal processor. A rear cameraand a flash (not shown) may be disposed to a second cover, i.e., a rearface, of the housing. The flash may include, for example, a LightEmitting Diode (LED) or a xenon lamp. In some embodiments, two or morelenses (wide angle and telephoto lenses) and image sensors may bedisposed to one face of the electronic device 100.

At least one or more sensors 124 according to various embodiments maygenerate an electrical signal or data value corresponding to an internaloperational state of the electronic device 100 or an externalenvironmental state. The sensor 124 may include an optical sensor, e.g.,a proximity sensor, and may include a fingerprint sensor, a biosensor,or the like (not shown). For example, the fingerprint sensor may bedisposed to the first face (front face) or second face (rear face) ofthe housing 111. In addition, the electronic device 100 may furtherinclude at least one of senor modules (not shown), for example, agesture sensor, a gyro sensor, an atmospheric pressure sensor, amagnetic sensor, an acceleration sensor, a grip sensor, a color sensor,an Infrared (IR) sensor, a temperature sensor, a humidity sensor, and anilluminance sensor.

The indicator 123 according to various embodiments may be disposed, forexample, on a first face of the slider 120. The indicator 123 mayprovide state information of the electronic device 100 in a form oflight, and may include an LED.

FIG. 3 is a cross-sectional view illustrating an electronic device inwhich a slider is inserted according to various embodiments of thedisclosure. FIG. 4 is a cross-sectional view illustrating an electronicdevice in which a slider is withdrawn to expand a display area accordingto various embodiments of the disclosure. FIG. 5 is an exemplary viewillustrating a structure of a smoothness maintaining device mounted onan electronic device according to various embodiments of the disclosure.

Referring to FIG. 3 to FIG. 5, an electronic device 300 according tovarious embodiments of the disclosure may be the same electronic deviceas the electronic device 100 of FIG. 1 and FIG. 2. The electronic device300 according to various embodiments may include a support body 340 anda smoothness maintaining device to maintain smoothness of an expandeddisplay area of the flexible display 330 when a slider 320 is withdrawnfrom a housing 311.

The support body 340 according to various embodiments may be disposedclosely in contact with a bottom face of the expanded display area (134of FIG. 2), and thus, when the expanded display area is exposed to theoutside, may serve for a function of supporting the expanded displayarea, as a support base playing a role of a prop of the expanded displayarea. The support body 340 may be configured integrally in the expandeddisplay area. For example, a detailed configuration for the support body340 will be described with reference to FIG. 7A to FIG. 7C.

The smoothness maintaining device according to various embodiments mayserve for a function of maintaining smoothness of the support body 340to maintain smoothness of the expanded display area of a flexibledisplay 330.

The flexible display 330 according to various embodiments may have oneend 330 a fixed to the slider 320 and the other end 330 b fixed to thesupport body 340. Therefore, according to an operation of inserting orwithdrawing the slider 330, the support body 340 and the expandeddisplay area of the flexible display 330 may be withdrawn to the outsidefrom the housing 311 or may be inserted into the housing 311.

The smoothness maintaining device of the expanded display area accordingto various embodiments may include first and second rollers 341 and 342and a wire 343. The smoothness maintaining device may be disposedbetween the flexible display 330 exposed to the outside and a bottomface 311 b of the housing 311. The first roller 341 may be constructedin pair, and the second roller 341 may be constructed in pair. The firstand second rollers 341 and 342 may be disposed to face each other. Eachof the first and second rollers 341 and 342 may be disposed in thehousing 311 in a rotatable manner, and may include a bearing (notshown).

The smoothness maintaining device according to various embodiments mayinclude the first roller 341 disposed at a first position of the housing311, the second roller 342 disposed at a second position of the housing311, and the wire 343 configured such that one end 343 a and the otherend 343 b move in opposite directions from each other by means of thefirst roller 341.

The one end 343 a of the wire according to various embodiments may becoupled to one end 340 a of the support body 340, and the other end 343b of the wire may be coupled to the other end 340 b of the support body.Thus, tension force is provided to pull both ends of the support body340, thereby providing force for maintaining smoothness of the supportbody 340. Since the expanded display area of the flexible display 330 isdisposed closely in contact with the support body 340, a structure ofmaintaining the smoothness of the support body 340 may maintain thesmoothness of the expanded display area. The support body 340 is pulledin a direction in which both ends thereof are away from each other,thereby maintaining a taut state. The taut state (tight state) is astate where the support body retains tension, and may be referred to asa smoothness maintaining state.

The electronic device 300 according to various embodiments may havevarious components disposed to a mounting space between the support body340 and the wire 343. For example, the component disposed to the spacein the housing 311 may include a printed circuit board, a battery, anantenna, or the like.

In the wire 343 according to various embodiments, one end 343 a and theother end 343 b may move in opposite directions from each other by meansof the first roller 341. For example, when the one end 343 a of the wiremoves toward the second roller 342, the other end 343 b of the wire maymove from a position around the second roller 342 to a position close tothe second roller 342. Each of the one end 343 a and the other end 343 bof the wire may move in a direction parallel to the flexible display 330while maintaining a specific interval. As will be described below, thefirst roller 341 is provided with elastic force in a direction away fromthe second roller 342, so that the wire 343 and the support body 340always retain tension (tension force).

The first roller 341 according to various embodiments may be constructedin pair, and may be disposed substantially to an intermediate area ofthe housing 311 in a rotatable manner along a first rotation axis in adirection perpendicular to an inserting/withdrawing direction. Thesecond roller 342 according to various embodiments may be disposedsubstantially to a lower end area of the housing 311 in a rotatablemanner along a second rotation axis in a direction perpendicular to theinserting/withdrawing direction. The first and second rollers 341 and342 may be disposed to be symmetric with each other, and may face eachother. The first roller 341 may interwork with the wire 343, and thesecond roller 342 may be disposed to interwork with the support body340. In addition, the first roller 341 may rotate in a state of being incontact with the wire 343, and the second roller 342 may rotate in astate of being in contact with the support body 340.

For example, when the slider 320 is inserted or withdrawn, each of thefirst and second rollers 341 and 342 may rotate. At the same time, thewire 343 and the support body 340 may also move.

In a state where the slider 320 is inserted to the housing 311 (e.g.,FIG. 3), part of the support body 340 may be in a state of being incontact with an outer circumferential face of the second roller 342, andthe rest of it may be disposed adjacent to the second cover 311 b of thehousing 311. In a state where the slider 320 is withdrawn from thehousing 311 (e.g., FIG. 4), part of the support body 340 may be in astate of being in contact with the outer circumferential face of thesecond roller 342, and the rest of it may be disposed as a prop of theexpanded display area.

In addition, in a state where the slider 320 is inserted to the housing311, part of the wire 343 may be in a state of being in contact with anouter circumferential face of the first roller 341, and the rest of itmay be in a state of being disposed to have a gap at a bottom face ofthe expanded display area. In a state where the slider 320 is withdrawnfrom the housing 311, part of the wire 343 may be in a state of being incontact with the outer circumferential face of the first roller 341, andthe rest of it may be adjacent to face the second cover 311 b of thehousing.

FIG. 6 is an exemplary view briefly illustrating a state where a firstroller of a smoothness maintaining device is supported by an elasticbody according to various embodiments of the disclosure.

Referring to FIG. 6, a smoothness maintaining device according tovarious embodiments may further include an elastic body 650. The elasticbody 650 is a compression coil spring, and may provide force for pullingthe first roller 641 in a direction away from the second roller 642.Since the first roller 541 is always provided with the force away fromthe second roller 642, a support body can always retain force forsmoothness, and an expanded display area can maintain the smoothness.For example, the elastic body 650 is not limited to the spring. In theelastic body 650 according to various embodiments, one end may be fixedto part of the housing 610, and the other end may be fixed to a shaft‘s’ of the first roller.

FIG. 7A to FIG. 7C are cross-sectional views illustrating variousexamples of support bodies according to various embodiments of thedisclosure.

Referring to FIG. 7A, a support body 740 according to variousembodiments may be configured in the same manner as the support body 340of FIG. 3 to FIG. 5. The support body 740 according to variousembodiments may include a flexible film 741, and a plurality ofprotrusions 742 attached to one face of the flexible film 741. Theflexible film 741 may include a first face 741 a closely in contact withone face of the flexible display, and a second face 741 b facing awayfrom the first face 741 a.

The protrusions 742 according to various embodiments may be disposedwith an equal interval on the second face 741 of a flexible film along adirection (an X-axis direction) perpendicular to aninserting/withdrawing direction. However, the protrusions 742 are notnecessarily limited to being disposed with the equal interval, and maybe disposed to be coupled with each other.

For example, a cross-section of the protrusion 742 may be configured inan isosceles trapezoidal shape. However, the cross-section of theprotrusion 742 is not limited to the isosceles trapezoidal shape, andmay be configured in a shape of quadrangle, square, rectangle,semicircle, or the like. For example, each of the protrusions 742 may beconstructed of a Poly Oxy Methylene (POM) material.

The flexible film 741 according to various embodiments may be configuredto have substantially the same area as the expanded display area. Inaddition, an area in which the plurality of protrusions 742 are disposedmay be substantially similar to a size of the flexible film 741, and maybe substantially similar to the expanded display area.

Referring to FIG. 7B, a support body 743 according to variousembodiments may include a film portion 744 and a plurality ofprotrusions 745 which are integrally injection molded to the filmportion 744. For example, the film portion 744 and the protrusion 745may be produced integrally. Each of the protrusions 745 may be disposedon one face of the film portion 744 with an equal interval in adirection perpendicular to an inserting/withdrawing direction of aslider.

For example, a cross-section of the protrusion 745 may be configured inan isosceles trapezoidal shape. However, the cross-section of theprotrusion 745 is not limited to the isosceles trapezoidal shape, andmay be configured in a shape of quadrangle, square, rectangle,semicircle, or the like.

Referring to FIG. 7C, a support body 746 according to variousembodiments may include a film portion 747 and a plurality ofprotrusions 748 which are integrally molded to the film portion 747. Forexample, the film portion 747 and the protrusion 748 may be producedintegrally. The protrusions 748 may be disposed on one side face of thefilm portion 747 so as to be in contact with each other in a directionperpendicular to an inserting/withdrawing direction of a slider.

For example, a cross-section of the protrusion 748 may be configured inan isosceles trapezoidal shape. However, the cross-section of theprotrusion 748 is not limited to the isosceles trapezoidal shape, andmay be configured in a shape of quadrangle, square, rectangle,semicircle, or the like.

FIG. 8 is a cross-sectional view illustrating an anti-scratch device ofan expanded display area according to various embodiments of thedisclosure.

Referring to FIG. 8, an electronic device 800 according to variousembodiments may be the same electronic device as the electronic device100 of FIG. 1 and FIG. 2. A housing 811 of the electronic device 800according to various embodiments may further include an anti-scratchdevice 860 of an expanded display area 834, in proximity to a secondroller 842. When a slider is inserted or withdrawn, the expanded displayarea 834 may be scratched in some lower end portions of the housing 811while being inserted or withdrawn. Thus, the anti-scratch device 860 maybe disposed in a portion of the housing 811 which may be interfered withthe expanded display area 834.

The anti-scratch device 860 according to various embodiments may bedisposed to a lower end of the housing 811, and may be configured as atleast one anti-friction member disposed to face at least part of anouter circumferential face of the second roller 842.

FIG. 9 is an exemplary view briefly illustrating an automaticinserting/withdrawing device included in an electronic device accordingto various embodiments of the disclosure.

Referring to FIG. 9, an electronic device 900 according to variousembodiments may be the same electronic device as the electronic device100 of FIG. 1 and FIG. 2. The electronic device according to variousembodiments may automatically configure a driving source for performingan operation of inserting or withdrawing a slider in a main body.

For example, a device for automatically inserting/withdrawing the slidermay include a gear G provided coaxially with a first roller 941, adriving motor M, and a gear box B disposed between the gear G and thedriving motor M to decrease a rotation count of the driving motor M. Thegear box B may be configured as an array of at least one gear.

In addition, a rack 331 to be engaged with the gear may be furtherincluded in the slider. The rack 331 is illustrated in FIG. 4.

When the driving motor M is driven, rotation force is transferred to thegear box B, and the transferred rotation force is transferred to thegear G. According to the rotation of the gear B, the first roller 941also rotates simultaneously. The slider may be inserted or withdrawn dueto the rack 331 engaged with the gear G. According to inserting orwithdrawing of the slider, the flexible display may also be inserted orwithdrawn.

Various embodiments of the disclosure disclosed in the specification andthe drawing are merely a specific example presented for clarity and arenot intended to limit the scope of the disclosure. Therefore, inaddition to the embodiments disclosed herein, various changes in formsand details made without departing from the technical concept of thedisclosure will be construed as being included in the scope of thedisclosure.

The invention claimed is:
 1. An electronic device comprising: a housingincluding a first cover disposed to face a first direction, a secondcover disposed to face a second direction opposite to the firstdirection, and a side member enclosing at least part of a space betweenthe first and second covers; a slider to be inserted or withdrawn bybeing disposed to at least part of an area of the first cover of thehousing; a flexible display disposed in the slider such that at leastpart thereof is exposed, and disposed to allow a display area to beexpanded according to the withdrawing of the slider and allow theexpanded display area to be hidden inside the housing; and a flexiblesupport body mounted closely in contact on a bottom face of the flexibledisplay, supporting the expanded display area as a prop when the slideris withdrawn, and disposed to be housed inside the housing together withthe expanded display area when the slider is inserted, wherein tensionis applied to the support body to thereby maintain the support body in ataut state.
 2. The device of claim 1, further comprising a smoothnessmaintaining device of the expanded display area when the slider iswithdrawn, wherein the smoothness maintaining device is coupled to eachof one end and another end of the support body to provide force forpulling each of the one end and the other end in a direction in whichthe one and other ends are away from each other.
 3. The device of claim2, wherein the support body is fixed closely in contact to the expandeddisplay area in an integral manner to move together with the flexibledisplay.
 4. The device of claim 3, wherein the smoothness maintainingdevice comprises: at least one first roller rotatably disposed at afirst position of the housing; a second roller facing away from thefirst roller, and rotatably disposed at a second position of thehousing; and at least one wire configured such that one end and anotherend thereof are movable in different directions, wherein the one end ofthe wire is coupled to the one end of the support body and the other endof the wire is coupled to the other end of the support body to providetension force for maintaining a smoothness state of the support bodytogether with the first and second rollers.
 5. The device of claim 4,wherein the one end and the other end of the wire move in parallel withthe flexible display while maintaining a specific interval from eachother.
 6. The device of claim 4, wherein the wire is located to face thesecond cover of the housing when the slider is withdrawn, and is locatedto face a bottom face of the support body when the slider is inserted.7. The device of claim 4, wherein the first roller rotates in a state ofbeing in contact with the wire, and the second roller rotates in a stateof being in contact with the support body.
 8. The device of claim 4,wherein the support body is disposed to a bottom face of the expandeddisplay area of the flexible display when the slider is withdrawn, andis disposed to face the second cover of the housing when the slider isinserted.
 9. The device of claim 8, wherein the one end and the otherend of the support body move in parallel with the flexible display whilemaintaining a specific interval from each other.
 10. The device of claim8, wherein the support body comprises: a flexible film including a firstface closely in contact with one face of the flexible display, and asecond face facing away from the first face; and a plurality ofprotrusions disposed with an equal interval on a second face of theflexible film along a direction perpendicular to aninserting/withdrawing direction.
 11. The device of claim 10, wherein anarea in which the plurality of protrusions are disposed is substantiallythe same as the expanded display area.
 12. The device of claim 10,wherein the plurality of protrusions are configured to be spaced apartfrom each other, or are configured integrally to be disposed with anequal interval.
 13. The device of claim 4, wherein the first rollerfurther comprises an elastic body so that force is provided in adirection away from the second roller.
 14. The device of claim 4,wherein the housing further comprises an anti-scratch device of theexpanded display area, in proximity to the second roller, and whereinthe anti-scratch device is disposed to a lower end of the housing, andis configured as at least one anti-friction member disposed to face atleast part of an outer circumferential face of the second roller. 15.The device of claim 4, further comprising: a gear provided coaxiallywith the at least one first roller; and a rack gear engaged with thegear and included in the slider.